1. Field of the Invention
The present invention relates to a method of recording still pictures and audio data onto a rewritable recording medium.
2. Description of the Related Art
A disk-type recording medium such as a compact disk (CD) can store high-quality digital audio data permanently, so that it is very popular recording medium. Recently, a digital versatile disk (referred as ‘DVD’ hereinafter) has been developed as a new disk-type recording medium. A DVD can store much larger size than a CD, thus, high-quality moving picture or audio data are recorded on a DVD for much longer time. Therefore, a DVD will be used widely in the near future.
There are three types of a DVD, DVD-ROM for read-only, DVD-R for write-once, and DVD-RAM or DVD-R/W for rewritable. For a rewritable DVD, the standardization of data writing format is being finished.
In these days, a digital TV broadcast being capable of carrying TV programs of HD (High-Definition) quality is in service. Thus, a new high-density recording medium is being developed to record digital TV programs of such quality. The new high-density recording medium targets about 23 GBytes in storage capacity that is about five times of a DVD. Standardization of application specification of that recording medium is in progress among several related companies. If the high-density recording medium is commercialized in near future, motion picture data and many still pictures can be stored on a single high-density recording medium.
In addition, a Digital Still Camera (DSC) being capable of storing a taken picture in the form of digital data has been developed recently. Such a DSC usually has a memory chip of large storage capacity so that it can take high-quality pictures and store audio data associated with the stored pictures as well. In a DSC, the taken pictures are encoded in the format of JPEG, or TIFF while the audio data are done in the format of PCM, u-Law PCM, or IMA-ADPCM.
A DSC has a well-known file system called DCF (Design rule for Camera File system) for recording still pictures and audio data. FIG. 1 shows an illustrative DCF. In the structure of DCF, a DCIM (Digital Camera IMages) directory exists under a root directory and many subdirectories may exist under the DCIM. Each subdirectory has 8-digit-long filename that is composed of three numeric digits and five character digits. The three numeric digits should be unique, for instance, one among 100-999, and the five character digits are arbitrarily chosen by a user. Because the three numeric digits are unique the subdirectories can be created up to 900.
A subdirectory, e.g., subdirectory ‘100ABCDE’ of FIG. 1 can accommodate many data files of which filename is 8-digits long. The filename is composed of four numeric digits and four character digits. While the four character digits are chosen by a user the four numeric digits should be unique among data files if their attributes are different. The data files are still pictures and/or audio files, respectively. The still picture files have extension of ‘JPG’ or ‘TIF’ while the audio files encoded by PCM, u-Law PCM or IMA-ADPCM have extension of ‘WAV’. The filenames of the data files can be same if their extensions are different. Therefore, when a picture file is to be index with audio, an index audio file can be linked with the picture file only if their filenames are made same.
By the way, a disk video recorder (DVR), which has been developed recently, can record still pictures and audio data as well as motion pictures onto a disk recording medium. If a DVR adopts its file recording structure being able to improve compatibility with a DSC for still picture and audio data, a user can move or copy between a DVR and a DSC without any data conversion or any data converting tool or with a very simple converting tool. This will improve use convenience of the two electronic machines remarkably.